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Dry out ABS temperature and time?

Posted by tmorris9 
Dry out ABS temperature and time?
May 20, 2014 06:55PM
So I have a few rolls of ABS that don't print well from Lulzbot, they tell me it's due to moisture in the ABS. I have a PID controlled convection toaster oven (I built it years ago for accuracy with polymer clay).

I just need to know the proper temperatures and time to bake the moisture out without melting it.

FYI I tired a small roll in the car as I have seen mentioned and it melted the lip of the spool, it bent over at a 45deg angle.

Re: Dry out ABS temperature and time?
May 20, 2014 07:40PM
A few notes I have collected:

ABS, (Acrylonitrile butadiene styrene, Type: extruded):

Drying Temperature:
Range: 70°C to 93.3°C, (158ºF to 200ºF).
Average: 80.9°C, (178ºF ).

Dry time:
Range: 2 to 4 hours.
Average: 3.2 hours.

Glass-transition temp:
Range: 108°C to 109°C.
Average: 108°C, (226.4ºF ).
Wikipedia: 105°C, (221ºF ).

Begin testing around this temp:
Substrate/bed temperature: <105°C, (221ºF ).
Enclosure temperature: <105°C, (221ºF ).

Material properties are generally stable between:
−20 and 80 °C (−4 and 176 °F).

Linear Mold Shrinkage (extruded):
0.002 – 0.008 cm/cm.
Average value: 0.00532 cm/cm.

Machine parameters:
Extrude temp (RepRap): 210 C ~ 240 C

1. drop your bed temp to 80 after the first layer, and maybe drop your extruder to 220. A 110 bed will actually release easier that at 80, and will cause warping to the perimeter of your print. [forums.reprap.org]

2. we prefer a low water absorb grade ABS, natrual color is white, not yellow base, you don't need to dry it. However, the colors of ABS filament will absorb water severely, since the colors tones are easily absorb water, not ABS materials;

3. For drying resin without dessicant in this type of oven, I normally dry it at about half the molding temp. For ABS molding at 440° (227°C) I dry it at around 212°F (100°C) for 2 to 4 hours. For extruding, you don't need it as dry as much as for injection molding. Injection molding uses far higher injection pressures and even the slightest moisture will lead to surface defects on the plastic parts. Extruding only makes the plastic flow at a much, much lower pressure, so slight moisture isn't a big problem.

4. Extrusion temperature has a lot to say. If i print ABS at 240C the entire room I’m printing in will stink of molten ABS. If i print at 230C there’s nary a smell at all. At 235C It smells, but it’s not as bad.
Re: Dry out ABS temperature and time?
May 20, 2014 09:30PM
Thanks for the info.
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